Carpet and preparation thereof

ABSTRACT

A highly satisfactory carpet is prepared by applying to the back of a filamentary carpet a mixture of expandable microspheres and a film forming binder, drying and foaming the mixture on the carpet back. The resultant backed carpet shows excellent resiliency and resistance to permanent set.

United States Patent [191 Ervin et a1.

[ June 25, 1974 CARPET AND PREPARATION THEREOF [75] Inventors: Gary D.Ervin, Delran, N.J.; Harold A. Walters, Beaverton, Mich.

[73] Assignee: The Dow Chemical Company,

Midland, Mich.

22 Filed: Nov. 6, 1972 211 Appl.No.:304,045

Related U.S. Application Data [63] Continuation-impart of Ser. No.199,807, Nov. 17,

1971, abandoned.

[52] U.S. Cl 161/64, 161/67, 156/72, 156/79 [51] Int. Cl D04h 11/00 [58]Field of Search 156/72, 79; 161/64, 67

[5 6] References Cited UNITED STATES PATENTS 3,585,099 6/1971 VanBuskirk 161/67 Primary ExaminerWilliam J Van Balen Attorney, Agent, orFirm-Robert B. lngraham 7 Claims, No Drawings CARPET AND PREPARATIONTHEREOF This application is a continuation-in-part of our copendingapplication Ser. No. 199,807, filed Nov. 17, 1971, now abandoned.

This invention relates to an improved carpet and the preparationthereof.

Many carpets are prepared which consist of a low cost backing materialsuch as jute or the like through which filaments are positioned toprovide a plurality of tufts extending on one side thereof to form thenap of the carpet. Such carpets are often installed over a resilientbacking or an integral resilient backing such as a latex foam is appliedthereto. Oftentimes rubber or latex foam resilient backing adhered tothe scrim or back of the carpet is of very low strength and oftentimesof minimal resiliency.

It is an object of the present invention to provide an improved backedcarpet and to provide an improved method for the preparation of suchcarpet.

It would be desirable if there were available an improved method for thepreparation of carpet which permitted the rapid application andformation of a resilient backing.

These benefits and other advantages are achieved in accordance with thepresent invention in an improved carpet comprising a supporting scrimhaving extending from at least one side thereof a nap composed of aplurality of filaments, a resilient backing adhered remote from saidextending filaments, the resilient backing comprising a plurality ofsynthetic resinous hollow gasfilled microspheres, the hollowmicrospheres having a polymer shell, the polymer shell having a glasstemperature (Tg) of at least 50C. and a bulk density of about 0.25 toabout 5 pounds per cubic foot, the microspheres being contained in asynthetic resinous thermoplastic matrix having a glass transitiontemperature of from about -S0C. to about +20C.

Also contemplated within the scope of the present invention is a methodfor the preparation of a backed carpet, the steps of the methodcomprising providing a carpet having a plurality of filaments extendingfrom at least one side thereof, a supporting scrim supporting thefilaments, applying to the carpet remote from said extending filaments afoam forming composition comprising in intimate admixture an aqueousdispersion containing from about to 85 parts by weight of a film formingsynthetic resinous latex binder and from about 85 to about l5 parts byweight of expandable synthetic resinous microspheres, the expandablemicrospheres having a synthetic resinous thermoplastic shell havingsymmetrically encapsulated therein as a distinct and separate phase avolatile fluid raising agent, heating the dispersion to a temperaturesufficiently high to remove water therefrom and cause the latex to forma matrix about the expandable microspheres, and heating to a temperaturesufficient to cause expansion of the microspheres to form a plurality ofgas-filled monocellular thermoplastic shells.

A wide variety of microspheres may be employed in the practice of thepresent invention. The particular chemical composition of themicrosphere shell and the fluid foaming agent within is not critical.The critical factor in the microspheres is the glass transition attemperatures of the polymer forming the shell. Many expandable syntheticresinous microspheres are known and such microspheres and thepreparation thereof are described in US. Pat. application Ser. No.634,691, now U.S. Pat. No. 3,615,972. Such microspheres and theirpreparation are also disclosed in Canadian Patent 752,45 1 and BritishPatent 1,044,680. Typical expandable microsphere compositions which areuseful are microspheres having a polymer shell of 60 parts by weightstyrene and 40 parts by weight acrylonitrile containing from about 15 to20 weight percent isobutane as the volatile fluid foaming agent. Otheruseful microsphere compositions are methylmethacrylate/acrylonitrile95:5 parts by weight with neopentane; polymethylmethacrylate withneopentane and polyethylmethacrylate with neopentane.

A wide variety of synthetic resinous latex materials may be employed asthe binder or film forming latex in the present invention. The precisechemical composition of the polymer of the latex is not critical. Thepolymer should be water insoluble and have a glass transitiontemperature between about -50C. and +20C., and should be film forming ata temperature at least about 10C. below the temperature at which theexpandable microspheres expand, and beneficially, about 30C. Typicallatex polymers which are suitable for the practice of the presentinvention include latex polymers of 60 weight percent styrene, 40 weightpercent butadiene; 67 weight percent methylmethacrylate, 33 weightpercent ethyl acrylate; 85 percent vinylidene chloride, 5 percent ethylacrylate; 10 percent butyl acrylate; 70 percent polybutadiene, 30percent acrylonitrile; weight percent vinyl acetate, '20 weight percentdiethylmaleate.

Other components may also be incorporated within the aqueous dispersionssuch as dyes, fillers, pigments, stabilizers for both light and heat,flame retarding agents and other additives commonly employed withaqueous latex dispersions and utilized with benefit.

Dispersions for the practice of the present invention are readilyprepared employing conventional latex formulating procedures, as theexpandable synthetic resinous microspheres are often available as a wetfilter cake containing from about 15 to about 40 weight percent water.No difficulty is encountered in admixing the latex and the microspheres.Generally formost coating operations it is desirable to incorporatewithin the composition a thickening agent such as the thickening orviscosity controlling agents conventionally used with latex coatingswhich include a wide variety of water soluble polymers including thesodium salt of polyacrylic acid, hydroxypropyl carbonate, cellulose,lecithin, gum agar and the like. As an alternate to thickening thelatex, a number of thin coats may be applied, dried and subsequentlyfoamed. Beneficially for most applications it is desirable to provide anaqueous dispersion having a viscosity between about 5 and 10 thousandcentipoise. The coating composition may be applied by any conventionalcoating procedure including spraying, rolling, doctoring, roll coatingand the like. Drying of the coating beneficially may be accomplishedprior to foaming, or drying and foaming accomplished simultaneously.Such drying and foaming conventionally may be accomplished bycirculating heated air, infrared heat and like heating methods wellknown to the art. Beneficially in some instances it is desirable toaccomplish the foaming between a pair of generally adjacent parallelbelts in order to obtain a product which has a constant thickness ifcontrol of coating weight is less than desired. Alternately, the coatingmay be pre- EXAMPLE 1 A coating formulation is prepared by mixing thefollowing ingredients in the order given with gentle agitation at roomtemperature: a latex of 54.9 percent solids (the latex polymer is acopolymer of 60 parts by weight styrene and 40 parts by weight butadiene(Tg lC.); 145.8 parts of the latex are employed); 27.8 parts water; a 10weight percent solution of sodium lauryl sulfate, 2 parts by weight;expandable microspheres having a polymer shell of a polymer of 49 partsby weight styrene, 32 parts by weight acrylonitrile (Tg 110C.)

' and containing encapsulated therein 19 weight percent neopentane,based on the weight of the polymer shell; 20 parts by weight of themicrospheres are used. Twelve parts by weight of an aqueous solution ofthe sodium salt of polyacrylic acid, 1 1.2 percent solids, are employed.The viscosity of the resultant solution is about 7500 centipoise. A 6inch square of tufted polypropylene carpet having polypropylene scrim iscoated with 20 grams of the foregoing formulation employing a roller.The coating is air dried and subsequently placed between spaced platensin a press. A metal sheet is disposed between the coating and the pressplaten and an asbestos pad is placed between the pile side of thecarpet. After 2.5 minutes, the coated samples are removed from the pressand have a foamed coating thereon about 0.15 inch thick of expandedmicrosphere polymer shells having a glass temperature of 50C. and a bulkdensity within the range of 0.25 to pounds per cubic foot. The backedcarpet is resilient, resists permanent set at ambient temperatures andis very acceptable for floor covering applications.

EXAMPLE 2 A coating formulation is prepared employing 139 parts byweight of the styrene/butadiene latex of Example l but with 57.5 percentsolids; 34 parts by weight water; 2 parts by weight of a percent aqueoussolution of sodium lauryl sulfate; parts by weight of expandablemicrospheres of Example 1; 5 parts by weight of the polyacrylic acidsolution of Example 1. The weight ratio of latex'solids to microspheresis 4: l. The viscosity of the solution is about 8500 centipoise. Twentygrams of the foregoing coating dispersion are applied to a 6 inch squareof polypropylene carpet having polypropylene scrim. The coated carpet isdried in a forced air oven at 240F. and foamed in a platen press at135C. as done in Example 1. The resultant sample shows good flexibility,resistance to significant permanent set at ambient temperatures, andresiliency with no tendency for the coating to flake.

EXAMPLE 3 A 20 gram portion of the coating formulation of Example 2 isapplied to a tufted polyethylene carpet with a polyethylene scrim anddried and foamed in accordance with Example 2. The resultant sampleshows good flexibility, resistance to significant permanent set atambient temperatures, and resiliency with no tendency for the coating toflake.

EXAMPLE 4 The procedure of Example 2 is repeated withthe exception thata tufted wool carpet having a jute scrim is employed. The backing showsgood flexibility, resilience, resistance to permanent set at ambienttemperatures, and resistance to flaking.

EXAMPLE 5 The procedure of Example 2 is repeated with the exception thata tufted filament nylon carpet with a polypropylene scrim is employed.Similar results are obtained.

EXAMPLE 6 The procedure of Example 2 is repeated with the exception thata tufted nylon carpet with jute scrim is employed. Similar results areobtained.

EXAMPLE 7 The procedure of Example 2 is repeated with the exception thata tufted acrylic carpet is employed having jute scrim. Similar resultsare obtained.

EXAMPLE 8 A coating formulation is prepared employing 170 parts byweight of a latex which is a polymer of percent vinylidene chloride, 10percent butyl acrylate and 5 percent acrylonitrile (Tg 30C); 8 parts byweight water; 2 parts by weight of a 10 percent solution of sodiumlauryl sulfate; 15 parts by weight of expandable microspheres of Example1, and 5 parts by weight of the polyacrylic acid solution employed inExample 1. The weight ratio of latex solids to microspheres is 85:15,and the resultant coating formulation has a viscosity of about 7500centipoise. A six inch square of tufted nylon carpet having a jute scrimis coated with 20 grams of the formulation and foamed in the manner ofExample 2. Similar results are obtained.

EXAMPLE 9 A coating formulation is prepared employing the followingingredients: parts by weight of a 50 percent solids latex of a polymerof 40 percent isobutylacrylate and 60 percent vinyl acetate (Tg 9C.); 13parts by weight water; 2 parts by weight of a 10 percent solution ofsodium lauryl sulfate; 20 parts by weight of expandable microsphereshaving a polymer shell of 80 percent methylmethacrylate, 20 percentmethyl acrylate (Tg 80C.) and containing encapsulated therein 33 partsby weight neopentane; 5 parts by weight of the sodium salt ofpolyacrylic acid. The weight ratio of latex solids to microspheres is4:1. Twenty grams of the formulation are applied to the back of a 6 inchsquare of tufted polypropylene carpet having a polypropylene scrim.Results similar to those of Example 2 are obtained.

EXAMPLE The procedure of Example 9 is repeated with the exception thatthe following coating composition is employed: 160 parts by weight of a50 percent solids latex of a polymer of 80 weight percent ethyl acrylateand weight percent styrene (Tg -3C.); l3 parts by weight water; 2 partsby weight of a 10 percent solution of sodium lauryl sulfate; 20 parts byweight of expandable synthetic resinous microspheres having a polymershell of a polymer of 94.5 percent methylmethacrylate and 5.5 percentacrylonitrile (Tg l 12C.). The microspheres contain 35 percentneopentane based on the weight of the polymer shell; 5 percent of thesodium salt of polyacrylic acid. The latex solid to microsphere ratio is4:1. The resultant composition is foamed in the manner of Example 9 andcommensurate results are obtained.

EXAMPLE 1 l The procedure of Example 1 is repeated employing thefollowing coating composition: 160 parts by weight of a 50 percentsolids latex of a polymer of 67 percent by weight butyl acrylate and 33percent acrylonitrile (Tg 40C. 13 parts by weight water; 2 parts byweight of a 10 percent solution of sodium lauryl sulfate; 20 parts byweight of expandable synthetic resinous microspheres having a polymershell of one part by weight methyl methacrylate and one part by weightmethyl methacrylate and one part by weight methyl acrylate (Tg 51C.).The expandable microspheres contain 31.5 percent neopentane based on theweight of the polymer shell; 5 parts by weight of the polyacrylic acidsolution of Example 1; the weight ratio of latex solids to microspheresis 80:20. Commensurate results are obtained.

In a manner similar to the foregoing examples, a wide variety of carpetsare provided with resilient backings in accordance with the presentinvention.

As is apparent from the foregoing specification, the present inventionis susceptible of being embodied with various alterations andmodifications which may differ particularly from those that have beendescribed in the preceding specification and description. For thisreason, it is to be fully understood that all of the foregoing isintended to be merely illustrative and is not to be construed orinterpreted as being restrictive or otherwise limiting of the presentinvention.

What is claimed is:

1. An improved carpet comprising a supporting scrim having extendingfrom at least one side thereof a nap composed of a plurality offilaments, a resilient backing adhered remote from said extendingfilaments, the resilient backing comprising 5 a plurality of syntheticresinous hollow gas-filled microspheres, the hollow microspheres havinga polymer shell, the polymer shell having a glass temperature of atleast 50C. and a bulk density of about 0.25 to about 5 pounds per cubicfoot, the microspheres being contained in a synthetic resinousthermoplastic matrix having a glass transition temperature of from about50C. to about +20C. 2. The carpet of claim 1 wherein the polymer shellof 15 the hollow microsphere is a copolymer of styrene andacrylonitrile.

3. The carpet of claim 1 wherein the shells are a copolymer of about 60parts by weight styrene and about 40 parts by weight acrylonitrile.

4. The carpet of claim 1 wherein the matrix is a polymer of styrene andbutadiene.

5. A method for the preparation of a backed carpet, the steps of themethod comprising providing a carpet having a plurality of filamentsextending from at least one side thereof, a supporting scrim supportingthe filaments,

. applying to the carpet remote from said extending filaments a foamforming composition comprising in intimate admixture an aqueousdispersion containing from about 15 to 85 parts by weight of a filmforming synthetic resinous latex binder and from about 85 to about 15parts by weight of expandable synthetic resinous microspheres, theexpandable microspheres having a synthetic resinous thermoplastic shellhaving generally symmetrically encapsulated therein as a distinct andseparate phase a volatile fluid raising agent,

heating the dispersion to a temperature sufficiently high to removewater therefrom and cause the latex to form a matrix about theexpandable microspheres, and

heating to a temperature sufficient to cause expansion of themicrospheres to form a plurality of gasfilled monocellularthermosplastic shells.

6. The method of claim 5 wherein the latex binder is a copolymer ofstyrene and butadiene.

7. The method of claim 5 wherein the expandable microspheres have ashell of a styrene-acrylonitrile polymer.

. UNITED STATES PATENT OFFICE- CERTIFICATE OF CORRECTION Patent No. 3819 463 Dated June 25 1974 lnventofls) Gary D. Ervin et a1 It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 5, lines 29 to 30, delete "and one part by weight methylmethacrylate".

Signed and sealed this 8th day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents (JRM PO-105CHO-59) -DC 60376-P69 u 5 (sovzumzm PRINTING OFFICE:930

2. The carpet of claim 1 wherein the polymer shell of the hollowmicrosphere is a copolymer of styrene and acrylonitrile.
 3. The carpetof claim 1 wherein the shells are a copolymer of about 60 parts byweight styrene and about 40 parts by weight acrylonitrile.
 4. The carpetof claim 1 wherein the matrix is a polymer of styrene and butadiene. 5.A method for the preparation of a backed carpet, the steps of the methodcomprising providing a carpet having a plurality of filaments extendingfrom at least one side thereof, a supporting scrim supporting thefilaments, applying to the carpet remote from said extending filaments afoam forming composition comprising in intimate admixture an aqueousdispersion containing from about 15 to 85 parts by weight of a filmforming synthetic resinous latex binder and from about 85 to about 15parts by weight of expandable synthetic resinous microspheres, theexpandable microspheres having a synthetic resinous thermoplastic shellhaving generally symmetrically encapsulated therein as a distinct andseparate phase a volatile fluid raising agent, heating the dispersion toa temperature sufficiently high to remove water therefrom and cause thelatex to form a matrix about the expandable microspheres, and heating toa temperature sufficient to cause expansion of the microspheres to forma plurality of gas-filled monocellular thermosplastic shells.
 6. Themethod of claim 5 wherein the latex binder is a copolymer of styrene andbutadiene.
 7. The method of claim 5 wherein the expandable microsphereshave a shell of a styrene-acrylonitrile polymer.